A television (TV) broadcasting system is now a situation that analog broadcasting and digital broadcasting are mixed. An analog TV system is very developing to broadcasting based on color from early broadcasting based on black and white. However, the analog broadcasting has shortcomings of transmission/reception difficulty, noise effect, and the like. Thus, interest of a digital TV system is increasing. Then, in the current territorial TV broadcasting system, a conventional analog broadcasting signal coexists with a digital broadcasting signal that Digital Multimedia Broadcasting (DMB) stands first on the list. In the territorial TV broadcasting, importance of digital broadcasting is increasing due to sudden increase of equipments that may receive the digital broadcasting signal, efficiency of the digital broadcasting method and stable transmission/reception of a broadcasting signal.
A digital TV (DTV) means a TV broadcasting system that processes all broadcastings of production, edition, transmission and reception by using a digital signal. Because the digital TV processes a different signal according to kind of information, the digital TV can overcome shortcomings of the analog TV that has low picture quality and sound quality and allows the user to see contents of only limited channel. The digital TV can remove noise, reduce overlap of a screen and provide more clean picture and voice than the conventional analog TV by using digital transmission technology. The digital TV can provide much more number of channels by compressing a signal without loss of information. Also, the digital TV can automatically correct a signal error that happens at a transmission process. The digital TV can share TV program and contents stored on Internet, and the like. There is advantage that the digital TV is available interactive communication with a user including internet search through TV. DTV method is divided into the American method, Advanced Television Systems Committee (ATSC), and the European method, Digital Video Broadcasting-Terrestrial (DVB-T). In ATSC, 8-level Vestigial SideBand (8-VSB) is used as a modulation method, and in DVB-T, Coded Orthogonal Frequency Division Multiplexing (COFDM) method is used as a modulation method.
Also, digitization of the broadcasting can secure good picture quality and sound quality and increase channel efficiency quadruple than an analog broadcasting system. In a viewer's side, digitization of the broadcasting can provide a high quality broadcasting service that is difficult to express in the analog broadcasting method, and can permit seeing and hearing of various programs provided through multi channels. In industrial side, digitization of the broadcasting can bring demand creation effect due to popularization of a digital broadcasting transmitter/receiver and popularization of new contents. Territorial DTV among the digital broadcasting systems is installed all over the country and now developing to country's basic network.
Hereinafter, the DTV transmission and reception system will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a DTV transmission system for transmitting a DTV broadcasting signal. The DTV transmission system of FIG. 1 has the same structure with prior DTV transmission system for transmitting a DTV broadcasting signal.
As shown, the DTV transmission system includes a broadcasting content provider 101, a modulator 102, a DTV transmitter 103 and a transmission antenna 104. The broadcasting content provider 101 receives broadcasting contents. The modulator 102 modulates the received broadcasting contents. The DTV transmitter 103 transmits the modulated signal. The transmission antenna 104 receives a data from the DTV transmitter 103 and transmits the received data through a radio medium.
Operating processes of the conventional DTV broadcasting system will be described with reference to FIG. 1 in detail. First, the broadcasting content provider 101 converts broadcasting content into a series of digital data in order to transmit the broadcasting content through a radio medium and transfers the converted digital data to the modulator 102. The modulator 102 modulates the broadcasting data based on a predetermined modulation method and transfers the modulated digital data to the DTV transmitter 103. The modulation method can be selected among an 8-VSB method, a COFDM method, and the like, according to the transmission method. The DTV transmitter 103 converts the broadcasting data received from the modulator 102 according to a DTV standard and transfers the converted broadcasting data to the transmission antenna 104. Here, the DTV standard means a standard of frequency, bandwidth and transmission speed, and the like. The transmission antenna 104 transmits the broadcasting data received from DTV transmitter 103 to a receiver through the radio medium.
FIG. 2 is a block diagram illustrating DTV reception system for receiving a DTV broadcasting signal.
FIG. 2 shows a receiver corresponding to a transmitter of DTV broadcasting system of FIG. 1. The DTV reception system of FIG. 2 is the same structure with prior DTV reception system for receiving a DTV broadcasting signal. The DTV reception system includes a reception antenna 201, a DTV receiver 202, a demodulator 203, a monitor 204 and a speaker 205.
Operating processes of the receiver of broadcasting system will be described with reference to FIG. 2 in detail. The reception antenna 201 receives broadcasting content transmitted from the transmitter of FIG. 1 and transfers the received broadcasting content to DTV receiver 202. The DTV receiver 202 outputs a DTV broadcasting signal of the selected channel. The demodulator 203 demodulates the DTV broadcasting signal by the same method as the modulation method used in the modulator 102 of the DTV transmission system, and extracts broadcasting content in the selected DTV broadcasting signal. The broadcasting content including video data and audio data is transferred to a viewer. The monitor 204 transfers the video data to the viewer, and the speaker 205 transfers the audio data to the viewer.
As mentioned above, the digital broadcasting system is enabled to transmit/receive the various additional signals by using a wide bandwidth.
Meanwhile, a country basic industrial net has various infrastructures. The infrastructure includes various systems and services, e.g., streetlights and traffic lights. The infrastructure is controlled by a predetermined method. For example, a control method of the streetlight will be described. On/off of the streetlight is controlled based on a sensor or a separate communication network. The control method using the sensor has a defect that error is large according to change of weather, climate and season. The control method using the separate communication network has a defect that initial installation cost or operational expense increases. A system or method that can control various infrastructures included in the basic industrial net efficiently is required.